Measurement / Analysis OptionsCSM/Win Software Features And Capabilities
Materials Development Corporation
offers the most advanced C-V plotting systems incorporating the
latest instrumentation and Windows software. The accuracy of MDC
CSM/Win Systems is unsurpassed and the variety of measurements and
analyses available is unmatched. Select from these menu options:
Accuracy and control are the key words
for MDC production C-V measurements. CSM/Win production software
offers a streamlined C-V plotting and bias-temperature stress program
with minimum operator input. A click of the mouse begins the measurement.
A single display shows all plots and test results. Password protection
allows a supervisor to preset all C-V measurement and stress cycle
parameters. Production test results may be saved for later retrieval
and analysis. Complete plots or just summaries may be stored. Data
can also be entered in the CSM/Win database for trend analysis using
various control charts.
C-V Measurement and Analysis
The user can select from three different
data gathering modes: Swept, Retrace or Pulsed. Each mode examines
the MOS device under different conditions. The Swept Mode finds
the substrate doping, flatband voltage, threshold voltage, and mobile
ion concentration. An important feature of the Swept Mode is the
Light Flash and Stabilization. This assures that the MOS device
has reached equilibrium inversion capacitance before the sweep begins.
Since the C-V sweep begins with the MOS device in inversion, errors
due to sweeping rate and inversion capacitance determination while
sweeping are eliminated. The result is a "textbook" C-V plot with
no anomalous glitches. The Retrace mode shows hysteresis due to
slow trapping or charge storage effects. The Pulsed mode prevents
inversion and measures the deep depletion MOS C-V data needed for
doping profile determination.
Conductance Measurement and Analysis
CSM/Win software uses conductance
to give a complete picture of MOS devices and to correct for series
resistance effects. MDC C-V plotters use both conductance and capacitance
measurements to plot true device capacitance and depletion region
conductance. Others just plot equivalent parallel capacitance or
equivalent series capacitance while neglecting the depletion region
conductance. The conductance of the MOS capacitor is more strongly
affected by interface charges than is the capacitance. Conductance
is directly proportional to loss in the MOS structure due to charging
and discharging of interface traps. Therefore CSM/Win Conductance-Voltage
plots give valuable information about interface traps. The unique
CSM/Win analysis of the conductance versus frequency characteristics
of an MOS sample is the most sensitive C-V interface trap detection
method and is capable of resolving charge densities in the low lO^m^eV"1
Doping Profile Analysis
CSM/Win software uses the comprehensive
Ziegler algorithm to convert pulsed MOS C-V data to a doping profile.
The doping profile is accurate from the oxide-semiconductor interface
to the maximum depletion depth and is therefore useful for low dose
ion implant monitoring. Peak doping, range, and total active dose
are computed. The technique is sensitive enough to resolve changes
in the substrate doping profile due to redistribution during oxidation.
Capacitance-Time Measurement and Analysis
The Capacitance-Time transient resulting
from an MOS device pulsed into deep depletion reveals important
information about bulk properties of the semiconductor and about
damage or contaminants introduced during processing. The Zerbst
analysis gives carrier generation lifetime and surface recombination
velocity. An additional analysis of lifetime versus depth can measure
lifetime uniformity in epitaxial layers and can detect differences
due to denuded zones or implant damage. Measurements can be made
at elevated temperatures to accelerate recovery time.
Measurement and Analysis
A comprehensive set of analyses for
junction diode or Schottky barriers begins with C-V data gathering.
The voltage step automatically adjusts to the slope of the C-V characteristics.
This assures an optimum set of C-V data whether the voltage range
is small or large. Doping and resistivity profiles are both available
at the click of a mouse. Plots of I/C^V or Log(C)-Log(V+())) show
doping uniformity and doping slope factor. Exclusive recalculation
options allow adjustment of stray capacitance and area to facilitate
calibration using a standard reference wafer of known resistivity.
Resistivity Profiling Option
Using a Mercury Probe, the user can
quickly measure the resistivity or doping level of a bulk wafer
or epitaxial sample. The program offers on-screen averaging of doping
or resistivity and a single detailed display of test results. The
optional Mercury Probe calibration software uses a reference standard
to automatically measure probe contact area and stray capacitance.
Trap Density Analysis Option
CSM/Win software offers interface trap density
analysis using both the Conductance-Frequency and Quasi-static techniques.
The Conductance-Frequency method is recommended for fine-tuning
of processes where the highest resolution is needed. The Quasi-static
technique is recommended where moderate to high levels of interface
traps are monitored, such as in radiation damage studies.
Voltage Sweep (TVS) Option
The TVS method measures the current-voltage
characteristics of an MOS device at high temperature. This technique,
which allows direct measurement of mobile ion movement, has higher
sensitivity and is much faster than the conventional CVBT measurement.
CSM/Win software uses a unique on-screen technique to accurately
analyze TVS data. The MDC QuietCHUCK DC Hot Chuck System contributes
to superior TVS data from the CSM/Win Systems.
CSM/Win Systems with an I-V option
can measure both MOS and diode structures. For junctions, both forward
and reverse bias curves can be analyzed. Junction ideality factor,
series resistance, and reverse saturation current are found. Solar
cells can be checked for efficiency. Oxide integrity of MOS devices
can be evaluated by various techniques such as Time Dependent Dielectric
Breakdown, Charge to Breakdown, and pulsed or ramped voltage. Present
data using histograms, cumulative failure plots, or Weibull plots.
Implant Analysis Option
Ion Implant Analysis software allows the
user to model implants with various doses, energies and cap materials.
Compute active dose, range, and straggle. The user can overlay theoretical
and actual plots for comparison.
Thin Film Transistor Measurements
The Thin Film Transistor measurement
option provides a menu of three-terminal tests to evaluate device
performance. Plots showing transfer, output and saturation characteristics
are measured. Special analyses include ION IOFF mobility, and threshold
Multiple Plot Overlay
The CSM/Win software makes it easy to overlay
plots from different measurements for comparison. Simply click and
drag one plot onto another to combine them.
The CSM/Win Help file is available at a mouse
click. It provides practical measurement information, details of
each measurement mode, specifications, and maintenance information.
The Help file also contains a collection of ideal and anomalous
plots, a reference list, and even a spare parts list. At over 500
pages, the CSM/Win Help file is an invaluable resource.
CSM/Win System software already provides
a spectrum of tests that span both production and engineering evaluations
of many types of semiconductor devices. MDC software engineers can
use their experience to develop custom applications for special
measurement needs. Modifications can range from a small variation
on an existing measurement to an entirely new test.
For more information on MDC product lines
visit their website at http://www.mdc4cv.com